The correct option is 1, 2 and 3 only.
Explanation
Bauxite is a non-ferrous metallic mineral and the primary ore used for extracting aluminium. It is formed through specific weathering processes in tropical and subtropical regions.
Statement-wise Analysis:
- Statement 1 is Correct: Odisha is the largest bauxite-producing state in India and holds the largest reserves. Major bauxite deposits are located in the Kalahandi, Koraput, Sundargarh, and Sambalpur districts.
- Statement 2 is Correct: Bauxite deposits are formed by the decomposition of a wide variety of rocks rich in aluminium silicates. The process involves the leaching of soluble constituents (like silica), leaving behind a residual mass of weathered material containing the ore.
- Statement 3 is Correct: Bauxite is the principal raw material for the production of alumina, which is subsequently smelted to produce aluminium. Aluminium is known for its strength, conductivity, and malleability.
- Statement 4 is Incorrect: Bauxite is typically associated with laterite rocks found on plateaus or hill ranges (e.g., the Amarkantak plateau, Maikal hills, and the plateau region of Bilaspur-Katni). Tertiary coal beds are associated with coal deposits found in North-Eastern states like Assam, Meghalaya, and Arunachal Pradesh, not bauxite.
Key Takeaway:
Bauxite is a residual ore formed by the weathering of aluminium silicate rocks. Odisha possesses the largest reserves in India, and the mineral is the primary source for aluminium production.